I. Field of the Invention
The present inventions relates to cooking utensils and, more particularly, to coating of a metal surface of the cooking utensils.
II. Description of Prior Art
During food preparation such as cooking, food has a tendency to stick to the surface of the cooking utensils, such as pots, pans, stoves, ovens, spatulas, and the like. When food sticks to the cooking utensil, the preparation of the food becomes more difficult, as does clean up thereafter. The typical approach to resolve such difficulties has been to treat or coat the surface of the cooking utensil in such a way as to impart more or less permanent non-stick properties thereto. Such efforts have met with commercial success but are in need of further improvement.
By way of example, one purportedly non-stick coating is provided with aluminum-based cooking utensils by hard anodizing the surface so as to build up an aluminum oxide layer thereon. That oxide layer reduces the tendency of the food to stick to the metal surface of the cooking utensil. However, the surface is still considered somewhat xe2x80x9cstickyxe2x80x9d meaning that an even slippier surface is desired. A further drawback to the hard anodized surface is the recognized inability to provide a white-colored surface to the cooking utensil. White coloration is desired by many making the hard anodized cooking utensil less desirable from a commercial perspective. Additionally, while various other colors are possible, exposure of the hard anodized surface to cooking heat, can cause the surface to become charred or discolored.
Another non-stick coating is provided by applying a layer of polytetraflouroethylene, i.e., Teflon(copyright) material, to the surface of the cooking utensil. The Teflon(copyright) coating is considered by some to be better than the hard anodized coating because it is slippier. There is thus less of a tendency for food to stick to the Teflon(copyright)-coated cooking utensil than the hard anodized cooking utensil. A significant drawback to the Teflon(copyright) coating, however, is that it tends to scratch or abrade thereby diminishing the non-stick behavior of the cooking utensil. The non-stick properties of Teflon(copyright) coated cooking utensils, once diminished or lost, such as from being scratched or abraded, may not be readily repaired.
Another non-stick coating is discussed in U.S. Pat. No. 4,677,147, which involves the reaction of four components, i.e., thermostable polyorganosiloxane resin, a nonthermostable polyorganosiloxane resin, and two different metal salts of carboxylicacids. The need to use two different varieties of siloxane, and the metals, introduces cost and complexity. Silane coatings for glassware is described in U.S. Pat. No. 6,054,522.
The present invention provides improved coatings for cooking utensils which is simpler than a multi-siloxane and metal reaction coating, imparts advantageous non-stick properties to the cooking utensil metal surface that are better than the hard anodized surface, and which may be readily repaired if scratched or abraded. To this end, and in accordance with the principles of the present invention, the surface of the cooking utensil is coated with an aqueous/alcohol silane solution which is then heated to form a more or less permanent, coating thereon. The resulting coating is thus easily applied to afford advantageous non-stick properties.
The silane solution may advantageously be comprised of components which when heated to temperatures commonly encountered in cooking food will form the coating. As a consequence, if the coating becomes scratched or abraded, it may be refurbished or renewed simply by applying an additional amount of the silane solution and heating same in a kitchen oven, for example. Such a procedure may be carried out at home by the consumer who may be provided with a quantity of the silane solution. Still further, the silane solution may advantageously contain only one variety of silane which is not reacted with any other variety of silane or non-native metals in order to be applied to, and form the coating on, the surface. It is contemplated that the silane reacts with the metal surface to form the non-stick coating. The silane is a trialkoxyalkane silane. One such solution includes only Bis(triethoxysilyl) ethane (BTSE) or Bis(trimethoxylsilyl) methane (BTSM).
The silane solution may also advantageously be provided with a colorant to impart visibly perceptible color to the coated surface. The colorant may include a white colorant to thereby impart a white surface to the cooking utensil. The coating formed by the silane solution is also resistant to charring or discoloring from heat and so can provide a stable color to the surface of the cooking utensil. Still further, the surface may be hard anodized prior to application of the silane solution to thereby create a coating over the hard anodized surface. The resulting coating provides advantageous non-stick properties, as well as a color stable appearance. The coating would also provide a sealant for the anodized aluminum coating.
By virtue of the foregoing, there is thus provided improved coatings for cooking utensils which is simpler than a multi-siloxane and metal reaction coating, imparts advantageous non-stick properties to the cooking utensil, and which may be easily repaired if scratched or abraded. These and other objects and advantages of the present invention shall be made apparent from the accompanying drawings and the description thereof.